Closure mechanism for cartons and files



Sept. 23, 1941. J. MANDEL y 2,256,834

CLOSURE MECHANISM FOR` CARTONS AND FILES v Filed' Jan. 27, 1958 2 sheets-sheet 1 INVENTOR Jco AMA/pf;

ATTORNEYS Patented Sept. 23, 1941 CLOSURE MLECHANISM FOR CARTONS AND FILES Jacob Mandel, New York, N. Y., assignor to Pronto File Corporation, New York, N. Y., a corporation of New York Application January 27, 1938, Serial No. 187,118

13 Claims.

The present invention relates to containers, especially to containers made of paper, such as corrugated board, and more particularly to paper cartons of the collapsible type, such as are employed, for example, as storage les of the shelf It is the general object of the invention to provide an improved closure mechanism for containers made of relatively thin material, such as paper cartons and the like.

More particularly, it is an object of the invention to provide an improved closure mechanism for the meeting ends of two cooperating flaps forming one of the walls of a paper carton, and especially the top wall of a shelf type of storage file.

It is a still further object of the invention to provide a closure mechanism for cartons of the type indicated, which is simple in construction and can be made from sheet metal with the aid of only a single die.

It is also an object of the invention to provide a closure mechanism which, in addition to its normal function of locking the carton in its closed position, also reinforces the carton against vertical pressure, thereby protecting the carton against distortion and its contents against injury.

It is a still further object of the invention to. provide a closure mechanism which is substantially at in shape, presenting no projections above the normal surfaces of the carton, and conforming quite closely to the normal outline of the carton.

The invention contemplates also the provision of a closure mechanism which is so constructed that in the closed condition of the carton, it will resist separating movement of the flaps, which it joins, in a direction transverse to the joined edges of the aps.

A still further object of the invention is the provision of a closure mechanism consisting essentially of two approximately flat plates provided with cooperating surfaces capable of interlocking directly with each other, that is, without the aid of a third member, to prevent separation of the parts to which they are attached in the plane of such interlocked plates.

VThese and other objects of the invention will appear more clearly from the following description taken in connection with the accompanying drawings, hereby made a part of this specification, in which drawings,

Fig. 1 is a view in perspective of one form of carton embodying a preferred form of the in- 55 wall of the le reliably in the closed position.

vention, the carton being shown as designed for use as a shelf type of storage le;

Fig. 2 shows a plan View of the carton or file, with the flaps constituting the top wall of the iile and secured to the side and end walls thereof, in the extended open position;

Fig. 3 is a top plan View of the closed file;

Fig. 4 illustrates a plan view of one of the metal stampings prior to attachmentto a free longitudinal edge of a top flap;

Fig. 5 shows a top plan View of the top wall aps in the partially closed position;

Fig. 6 represents a side View of the file in the condition shown in Fig. 5;

Fig. 7 illustrates an enlarged transverse section through the closure mechanism and is taken along the line 'I-l of Fig. 3; and

Fig. 8 is a vertical section taken along the line 8 8 of Fig. 7.

Referring to the drawings, there is shown in Figs-1 and 2, a collapsible file of known construction, the same being composed of side walls I0, front and rear end walls I I, a bottom wall I2, top aps I3 secured to the upper edges of the end walls, and top iiaps I4 secured to the upper edges of the side lwalls I0. In closing a carton of this type, the top flaps I3 are turned inwardly until they lie horizontally, after which the flaps I4 are bent inwardly until they overlie the flaps I3, as is well understood in the art.

Storage files of the type illustrated in the drawings are frequently heavily loaded with paper records and even with heavier objects. Upon being pulled off a shelf by means of a looped wire handle I5, the lile is subjected to considerable stress which tends to distort it. Also, the les are frequently stacked one above the other, and even if such stacking is only temporary, considerable vertical pressure is often imposed upon the middle portion of the top wall of the file where,` as will readily be seen, the le is least able to resist it. As the result of careless handlingor the placing of loads upon les of the shelf type, such les frequently become distorted and torn. so that their appearance and even their usefulness is destroyed. p

In accordance with the present invention, I provide a closure mechanism for cartons and les of the type indicated, which is extremely simple in construction, inexpensive to manufacture, neat in appearance and highly eiiicient for its intended purposes. The closure mechanism, forming the subject matter of my invention, is so constructed that it acts to hold the aps constituting the top while, at the same time, preventing distortion of the file and resisting Vertical pressure thereon.

In the form of the invention illustrated in the drawings, the closure mechanism comprises two metal stampings I6 and Il secured respectively to the facing free longitudinal edges of the top fiaps I4. Each of the metallic stampings or strips I6, II is provided, preferably toward its outer longitudinal edge, with one or more longitudinal reinforcing ribs i8 in the form of raised beads, the outer edges I9 being, if desired, so formed as to bite into the paper body of the flaps I4 to aid in securing the metallic strips to such fiaps. These longitudinal ribs, even though of relatively small dimensions, particularly in combination with the interlocking features shortly to be described, impart great strength to the closure mechanism and are able to resist considerable` vertical pressure without material distortion.

The rearward portions of the metallic strips I6 and I'I, that is the portions inwhich the rib or ribs I8 are located, are continuous; the forward portion is, however, in each case, formed of a series of projections 20, preferably rounded in form, as illustrated, the strip being cut out between the successive projections to provide tab or tongue portions 2l, the tab portions being preferably spaced from the projections, as can best be seen in Fig. 4. At the base or to the rear of the tab portions 2 I, the strip is provided with approximately semi-circular depressions to conform to the shape of the projecting portions 2D. The function of the depressions 22 will be made clear below. I The metallic strips are secured to the edge portions of the flaps I4A with the aid of the tabs or tongues 2 l. This is accomplished by bending the tabs about the edges of the flaps so as tov clamp or pinch the latter between the tabs and the overlying main portion of the metallic strips. To provide a firmer grip upon the flaps, which are usually made of corrugated or other paper board, the tabs may be punched or struck inwardly and, eXpanded asv shown at 23 ink Fig. '7, but if desired, and in order to grip the paper flaps even more securely, the depressed portions 22'may be forced inwardly as shown at 211 approximately above theexpanded portion 23.

As can be seen from Figs.l 1, 3 and 6, the metallic closure and reinforcing strips I5, Il are identical in formV but are arranged upon the respective flaps in staggered relation; that is, the projections 20 of one strip are arranged opposite the depressed portions 22 of the other strip. The spaces between the projections are preferably just large enough to admit. the projections ofthe cooperating strip withpa minimum of clearance in order that, when the projections are interngered, as shown in Figs. 1 and 3, a, practically continuous metallicV surface is obtained. The depressions 2,2 are just deep enough tol enable the overlying projections of the other strip, to lie approximately iiush at their upper surfaces with the surface of the mainbody portion of the strip containing such depressions. The interlocked strips thus present a smooth and substantially continuous surface which is practically dust-proof.

Byreason of the fact that each strip has projections overlying portions of the other strip, and inA turn has portions.Y which the projections ofthe other strip overlie, thev two flaps are brought into closed position by first interiingering; the opposite projections `while the flaps arer at angle, as shown in Figs 6 and; 7.. As the.-

two flaps are then brought to the horizontal, closed condition, the projections of each strip move into position within and over the depressed portions of the cooperating strip.

It will be noted that the strips at their interngering portions present a closure device having a multiple layer of metal along the facing edges of the flaps Ill, that is, where the carton or le is weakest. The closure thus presents considerable resistance to vertical pressure, and this resistance is increased by the ribs or beads I8.

The closure device also resists distortion of the carton under the influence of horizontal stress by reason of the engagement of the projecting portionsl against each other and especially of at least certain of the shoulders formed at the depressed portions 22 as indicated at 20a (see Figs. 3, 4 and 5). To provide additional resistance toward horizontal separating movement, especially in a direction perpendicular to the length of the strips, the projections may be provided with dents 25 which are c .rranged to be received within the dents 2.4 in the depressed portions 22, the dents 24 being insuch case made suiiiciently large and deep toreceive the down.- wardly expanded portions 25. The engagement of the parts 2e and 25 provides an interlock between the cooperating closure strips, which resists separation in the horizontal4 direction as viewed in Figs. 7. EitherV one orv both types of interlocks just described may be-employed; however, the closure means operates satisfactorilywithout these auxiliary holding or stop devices.

In addition to` the interlocking features hereinabove described, it is desirable also to provide the carton with locking means which will hold the naps IA against accidental opening movement. To this end, each metallic strip is pro.- videdv with `an end portion 2E. whichis-` bent downwardly over the edge of the flap and against `an end wall of the carton, as shown-in- Figs. 1

and 6. The end portion is providedwith a loop 2'! which may be struck from the body thereof and is designed to receive a hook-like member 28 pivoted 'at 23 upon the end wall of the casing and' provided with a finger piece 30, for moving it` into locking and releasing positions. While one locking: member 2 8 and cooperating loop 2'! are sufficient to hold the flaps in closed condition, I' prefer to provide such locking mechanism at both ends of the carton.

The metallic strips IBT and II' can b e suitably manufactured as metall stampings, and as' will be seen from the drawings, they are identical in construction, so that only one die or oneset of dies will be necessary. Because of'such identical construction, the locking portion 23'., 2] of the two strips will be positionedupon the opposite ends of the carton, so that, aside from they two hook members 28, no additional partsother than the strips themselves are required togprovide the locking feature at both ends of' the carton.

It will be seen` from the above that I have provided a closure mechanism forcartons, files` and the like, which canY be easily manu-factured on alarge scale at a very low cost, being composed of two identical stam-pings, the two parts of the closure acting to reinforce the cartonv against vertical pressure at its weakest part and resisting distortion of the container; The parts are also soshaped'and arranged that they are practically flush with the top sur-facel of the carton, the two. parts: ofv the closure. presenting` a smooth upper. surface even. though..

each includes portionswhich overlie parts of portions of the flaps with whichl they are asso- Hciated with the aid of parts of the closure itself, l

no additional fastening means being required.

Certain features of the invention hereinabove described may, of course, be used without others and various modifications of the structure described herein may be resorted to withinV the scope of the appended claims without departing from the spirit of the invention.

I claim: Y

l. A paper carton having side, end, and bottom walls and a cover including two flaps hingedly secured tothe top edges of the side walls and having theirv inner ends adjacent to each other in the closed condition thereof, and a closure device for the free edges of the said cover flaps, comprising two identical metal stampings secured to the free ends of said flaps and extending along the length thereof, each strip including a series of spaced, substantially at projections adapted to overlie the opposite flap, the interfingered projections in their closed position presenting a substantially fiat, metallic surface and being provided with cooperating holding means which are brought into position for interlocking when the closure device is in the closing position and are interengageable in a direction transverse to the free edges of the flaps, thereby resisting opening movement in the horizontal direction.

2. A paper carton having side, end, and bottom walls and a cover including two naps hingedly secured to the top edges of the side Walls and having their inner ends adjacent to each other in the closed condition thereof, and a closure device for the free edges of the said cover iiaps, comprising two identical metallic stampings, each formed of 4an integral strip of metal and having spaced projections extending from the body of said strip, the projections of one strip being in alignment with the spaces of the other strip, and the spaces between the projections of the respective strips being approximately of the same width as said projections to accommodate the staggeredly arranged projections of such opposite cooperating strips, the projections and the facing edges of the cover fiaps being so related that the projections on the flap overlie the other flap in the closed condition of the carton.

3. A carton as defined in claim 2, wherein the stampings are provided with longitudinal ribs to increase the strength thereof against vertical pressure.

4. A carton as defined in claim 2, wherein each of the metallic strips is provided with a depending side flange, the anges of the opposite closure members overlying opposite end walls, and means on said end walls arranged to cooperate with the flanges to hold the latter, and thus the cover aps, in their carton-closing position.

5. A carton as defined in claim 2, wherein each of said metallic strips is provided with depressed portions between the spaced projections, the forwardportions of the projections of each strip being adapted to rest upon the depressed portions of the opposite strip in the closed position of said strips, whereby the interlocking,

closed metallic strips present a substantially smooth upper surface in the closed condition of the carton.

'6. A carton Yas defined in claim 2, wherein the projections are Yprovided with depressed knobs, and the portions between the projections are provided with recesses adapted to receive such knobs in the closed conditionof the carton,

the interengagement ofV said knobs and recesses -acting tohold the fiaps against separation transversely of the metallic strips.

7. A paper carton having side, end, and bottomV walls anda cover including two flaps hingedly secured to the top edges of the side -vwalls and having theirinner ends adjacent to each other in the closed condition thereof, and

a closure device for the free edges of the said gcover iiaps, comprising twol identical metal stampings having spaced projections and secured tothe respective edges Yof the flaps in staggered, projection-interngering relation, the stampings Abeing secured to the iiaps'with the aid of integral tabs struck down from between the projections and bent around the longitudinal edges of the flaps, and means for locking the interngering closure members in the closed position of the flaps.

8. A paper carton having side, end, and bottom walls and a cover including two flaps hingedly secured to the top edges of the side walls and having their inner ends adjacent to each other in the closed condition thereof, and a closure device for the free edges of the said cover flaps, comprising metallic strips secured to the free ends of said flaps and extending along the length thereof, each of said strips having projections overlying the other strip, and means for securing one of the flaps to the end walls of the carton in the closed condition, the strip on such flap thus holding the second in closed position.

9. A paper carton having side, end, and bottom walls and a cover including two flaps hingedly secured to the top edges of the side walls and having .their inner ends adjacent to each other in the closed condition thereof, and a closure device for the free edges of the said cover flaps, comprising metallic strips secured to the free ends of said flaps and extending along the length thereof, said strips facing said edges and having interfingering projections each arranged to overlie the base of the strip of the opposite ap, and means for securing one of the aps to an end wall of the carton in the closed condition, said one flap then holding the other in the closed position.

10. A paper carton having side, end, and bottom walls and a cover including two flaps hingedly secured to the top edges of the side walls and having their inner ends adjacent to each other in the closed condition thereof, and a closure device for the free edges of the said cover flaps, comprising metallic strips secured to Y the free ends of said flaps and extending along the length thereof, each of said strips being constituted of a continuous portion overlying the marginal edge portion of its respective flap and spaced projections extending beyond the edge of the flap, the surfaces between and at the bases of the projections being depressed and being arranged to receive the projections of the opposite strip, whereby in the closed condition of the flaps, the interlocked strips present a smooth, continuous and substantially dust-proof closure.

11. A carton as set forth in claim 10, wherein the strips include tongues extending from the depressed surfaces and bent around the edges of the aps and biting into the undersurface of the latter to secure the strips thereto, said depressed surfaces being provided by depressions in the strips rearwardly of the tongues and being shaped to accommodate the projecting portions of the opposite strip.

l2. A paper carton having side, end, and bottom walls and a cover including two flaps hingedly secured to the top edges of the side walls and having their inner ends adjacent to each other in the closed condition thereof, and

a closure device for the free edges of the said cover flaps, comprising metallic strips secured to the free ends of said iiaps and extending along the length thereof, each strip including a series of spaced, substantially flat projections adapted to overlie the opposite flap, the interfingered projections in their closed position presenting a substantially flat, metallic surface.

13. A paper carton having side, end, and bottom walls and a vcover including ftwo Iiaps 'hingedly secured to the top edges ofthe side walls and having their inner ends adjacent to each other in the closed condition thereof, and a closure device for the free edges of the said cover flaps, `comprising interengaging metallic strips along the free ends of said top flaps each having alternatingA depressions and projections thereon, the depressions of one strip being adapted and arranged to receive the projections of the other strip, whereby the interngered strips in the closed position present a substantially continuous, flat, metallic surface.

JACOB MANDEL. 

